Prevalence of Gastrointestinal Parasites in the Frugivorous and the Insectivorous Bats in Southcentral Nepal

Abstract

Bats are the only active flying placental mammals and are traditionally classified into mega- and microbats, which are, respectively, herbivorous and insectivorous in feeding habit. Though deforestation, habitat destruction, natural calamities, illegal hunting, and climate changes are the challenging threats for bats, the role of existing gastrointestinal (GI) parasites have not been evaluated yet in Nepal. Thus, the current study aims to determine the prevalence of GI parasites in bats from the Shaktikhor area at the Chitwan district of Southcentral Nepal. From July 2018 to February 2019, a total of 60 fecal samples of bats (30 from frugivorous bats and 30 from the insectivorous bats) were collected. These samples were preserved at 2.5% potassium dichromate solution. The fecal examination was carried out by the direct wet mount, concentrations, acid-fast staining, and sporulation techniques. Overall results showed the prevalence rate of 80% GI parasites. The parasites detected in the insectivorous bats were Ascarid spp., Capillarid sp., Cryptosporidium sp., Eimeria spp., Entamoeba sp., Giardia sp., Hymenolepis spp., Isospora sp., Oxyurid sp., Strongyle, and Strongyloides sp. In contrast, Eimeria sp., Entamoeba sp., and Hymenolepis sp. were detected in the frugivorous bats. Based on a wide diversity of parasite richness and parasitic concurrency measured by the prevalence rates, we suggest that GI parasitism might be a threatening factor in the insectivorous bats in the current study area.

Figure 1

Map of the study area showing the locations of sample collections.

Figure 2

(a) Photograph of an insectivorous bat in the tunnel. (b) Photograph of a frugivorous bat.

Figure 3

Photomicrographs of various parasitic species. (a) Oocyst of Eimeria sp. (i) (20 × 14 μm), 400x, direct wet mount at Gram's iodine stain, in insectivorous bat. (b) Oocyst of Eimeria sp. (ii) (17 × 15 μm), 400x, after flotation technique at Giemsa's stain, in insectivorous bat. (c) Cyst of Entamoeba sp. (11 × 11 μm), 400x, direct wet mount at Lugol's Iodine stain, in insectivorous bat. (d) Oocyst of Isospora sp. (25 × 23 μm), 400x, after flotation technique, in insectivorous bat. (e) Egg of Ascarid sp. (54 × 36 μm), 400x, after sedimentation technique at Giemsa's stain, in insectivorous bat. (f) Egg of Toxocara sp. (50 × 49 μm), 400x, direct wet mount at 2.5% potassium dichromate, in insectivorous bat. (g) Light purple-colored egg of Hymenolepis sp. (52 × 43 μm), 400x, after flotation technique, in insectivorous bat. (h) Egg of Hymenolepis sp. (44 × 43 μm), 400x, after flotation technique, in frugivorous bat. (i) Brown-colored egg of Hymenolepis sp. (65 × 62 μm), 400x, after flotation technique in insectivorous bat. (j) Egg of Strongyloides sp. (87 × 46 μm), 400x, after sedimentation technique at Gram's iodine stain, in insectivorous bat. (k) Egg of Strongyle (83 × 41 μm), 400x, after flotation technique, in insectivorous bat. (l) Egg of Capillarid sp. (67 × 25 μm), 400x, direct wet mount at 2.5% potassium dichromate, in insectivorous bat. (m) Egg of Oxyurid sp. (93 × 36 μm), 400x, after flotation technique, in insectivorous bat.